Process for the extraction of metals from their ores.



No. 852,438. PATENTED MAY 7, 1907. R. LAMB.

PROCESS FOR-THE EXTRACTION OF METALS FROM THEIR ORES.

APPLIOATION FILED DBO.22,1902.

lxhbne we 3 v '11 oz RICHARD LAMB, OF NIWV YORK, N. Y.

PROCESS FOR THE EXTRACTION OF METALS FROM T HEIR ORES.

Specification of Letters Patent.

Patented May 7, 1907.

Application filed December 22,1902. Serial No. 136,106.

To all whom, it may concern.-

Be it known that I, RICHARD LAMB, residing at New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Processes for the Extraction of Metals from Their Ores, of which the following is a full, clear, and exact description, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to a process for the extraction of metalsfrom their ores. its object is to provide a process for the extraction of metals from their ores, particularly ad ted for the extraction of concentration of copper, which shall be of improved elliciency as compared with the processes now in use, and which shall be more economical, both from the standpoint of materials used and time consumed in carrying out the various steps of the process.

For the attainment of these and other objects, which will appear hereinafter, the process'consists in the various essential and supplemental steps hereinafter set forth, and

the novel features of wpich will be specilic-' ally pointed out in the c aims.

This process is especially adapted for the extraction of copper from its ores, and it will be herein described as in connection with a copper bearing ore, but it will be obvious that it is not necessarliy limited thereto.

In general, the process consists in agitating the ore, previously pulverized and roasted if necessary, in connection with a suitable solvent, forcing the solution together with the insoluble matter, into a filtering press, re-

moving the solution from the insoluble matter and extracting the metal from the solution by electrolysis .or otherwise.

I do not use the terms solvent and solution herein in a limiting sense, as it is not roast'tii'g turnace B, having a movable heatsupplying member B and a draft apparatus B with a suitable stack. In position to receive the ore dumped from the roaster B is a bin C. From this bin the ore is discharged into a car I), in connection with'which may be provided, for weighing the roasted ore. In position to receive the ore from the car D is a rotatable cylinder E, which is used for agitating or mixing the ore in connection with a suitable liquid. This cylinder has trunnions journalcd in staiulards l9, and it is adapted to be rotated by a suitably driven driven spur gear E meshing with an annular rack E on the barrel of the cylinder. Through stuffing boxes 1 I, pass pi pcs and G communicating with the interior of the cylinder E. Suit-able valves are provided for controlling the openings in these pipes adjacent the cylinder, as shown at F F The pipe N communicates with the interior of the cylinder, preferably in the vicinity of the axis thereof, while the pipe G is bent downwardly so that its mouth opens adjacent the lower part of the cylinder, as shown in dotted lines.

It will be understood, of course, that the cylinder is adapted to rotate independently of the communicating pipes N and G. A branch pipe N extends from pipe N and communicates with the draft apparatus B a suitable controlling valve N being provided in connection therewith adjacent to said draft apparatus. by pipe (1 with a filter ress M of usual construction. Below the fi ter press is a trough O which communicates, by means of pipes P P, with tanks H and I, through which tanks pass the heating coils J J. A bin Q, is in position to receive the solid matter removed from the filter press M, and such matter may .be discharged from this bin into a car D, from which it may be conveyed back to the mixer E. A pipe K connects the pipe G, from a point L adjacent the agitator I), with the tanks II and I, by suitable branches controlled by valves K and K. This pipe also communicates, by means of a suitable branch, controlled by the valve K, with a series of electrolytic cells It, Ii, It, to which current is supplied from a generator S. A valve K is provided in the pipe K between the point L where said pipe communicates with the pi e G and the point where the branch pipe ta (cs oil for the electrolytic cells, The electrolyte nay be discharged from the electrolytic cells into a vat U.

The Pip G is connected It will be understood that the mechanisms described above may be given any suitable proportion and arrangement of parts, and constructed of any suitable, material. The connections and relative positions of the various elements may be varied indefinitely, and the parts which are intended to resist pressure or to be used in connection with acids should be made pressure-proof and acid-proof. in extracting copper from its ores by my process, the roasting step is not always an essential one. When the ore is in a form to be lssolved by dilute sulfuric acid, as in the case of the oxids and carbonates of copper, it may be fed directly to the agitator. hen, however, there is an excess of alkali in the gangue, the oxid and carbonate ores are preferably roasted with suhid ore. This reduces the ore to the sulfate. it is then dissolved in hot water instead of in dilute sulfuric acid. In the case of suliid ores, the ore is roasted, preferably in a roaster or furnace, such that the temperature can be easily regulated in order to prevent the reduction of the metallic ores to a metallic state, and to change the iron to an oxid of iron, which is practically insoluble in dilute sulfuric acid, thereby also changing the sullids to sulfates.

The process may now be traced more specifically in conndction with the mechanisms illustrated. The ore is first crushed, then conveyed to the roaster B, which, as shown, is provided with means for easily regulating the temperature, as by the movable heat supplying member B. It is preferable that the ore should not be limited to a iixed time in passing through the roaster, but the furnace. should bc designed to retain the charge until it is shown by tests to be sulliciently roasted, although a type of furnace, in which the ore is conveyed in a continuous stream, or subjected for a fixed tim to the action of the heat, may be enlployed in some cases. The copper ore having been exposed to the action of a sullicicnt degree of heat in the furnace for a sullicient length of time, the moisture will be removed therefrom, and the iron will be changcd to an oxid of iron which is practically insoluble in dilute sulfuric acid. The degree of heal necessarv to effect this change varies within wide limits, but it may advantageously be about 700 degrees. it is desirable that. the ordinary oxidof iron in the ore should be cliangcd to an oxid of iron in-- soluble in dilute sulfuric acid, because thereby less of the acid will be consumed in the further stc'ps ,of the process. \Vhere the anguo contains much alkali, care should be taken to so proportion the roasting so as to form a minimum amount of oxid of copper. Loss care may be exercised where the non oxids and alkali are not excessive, for if part of the ore is roasted until it becomes oxid of copper, it can, in the further steps of my process, be economically treated with dilute suleeaase furic acid, which acid will later assist the process by rendering acidulous ,the not water electrolyte.

When the copper ore in the roaster has. been sufficiently roasted, whether to the extent necessary to reduce it to the sulfate or-to the oxid, or any other desired form, it is dumped from the furnace, which maybe ro-' the mixer by opening the valves K, K and if de- F, the valves K and K" being closed. sired, a suitable gage H maybe provided in connection with the tank ii, to indicate the amount of hot water which is run into the mixture. The mixer is then closed and rotated until the hot water has thorougl'ily dissolved all the sulfate of copper. "lhen,steam or compressed air is admitted from a suitable source of supply through the pipe N, the branch X connected with the draft apparatus being closed by the valve N nections between the mixer and the filter press having been opened and the branch connections to the tanks having been closed, the solution and the solid matter are thus pneumatically lorced front the mixer through the pipe G and into the filter press M. The

mixer is preferably kept rotating while under pressure. in order to hold the solid matter in suspension or solution, and to )revent its settliug to the lowest point of the mixer. By the action of the filter press, the hot water solution of copper is run into the trough '0. 'lhen the valve in the pipe P is opened and the solution is run into the tank Ii.- lhe filter press is now opened and the solid cakes, which may I c further treated, if desired, by continuing the supply of steam or compressed air through-the pipe M after the liquid has been pressedout, are dumped into the bin Q andtested for value. if enough oxid of copper is found therein, the ore is emptied from the bin Q into the car i) and conveyed hack to the mixer. Dilute sulfuric acid is then drawn from the tank I. into the mixer by opening the proper valves. A gage i on this tank may be used to indicate the supply of acid, if desired. When the proper proportion. of acid to ore has been run into the mixer,-the connections are closed and the mixer rotated. After thoroughly dissolving the oxid of copper, the solution and solid matter are again forced-under pressure into the filter press, the solution removed there from, and this solution is run into the tank l The conby opening the valve in the pipe 1" between said tank and the trough O.

in the case of the hot water solutlon, the same liquid may he run through several charges of ore, depending upon the amount of copper which the water will take into solution. As the sulfuric acid will take up only a richer electrolyte admits the efl'ectiye use of a greater current through the cells, and, ac-

' cordingly, the electrolytic step of the process can be carried out in less time.

The action of the coils J and J in supplying heat, both for warming the contents of the tanks, and for concentrating said contents by evaporation, will be readily. understood. The leached bre dumped into the bin Q, when it is found to contain nothing more of value, so far as the present process is concerned, may be disposed of in any desired and closing the valve K. The degree to which the valves K and K are opened respectively de ends upon the relative amounts of the two so utions whichit is desired to de liver to the electrolytic cells. The anodes and cathodes of the cells may be of any mate rial that will withstand the sulfuric acid undfir the action of the current. Lead answers t is urpos'e.

W lien the'copper has been extracted, the electrolyte may he led from the electrolytic cells into the tank I through the pipe T. When the electrolyte has become too foul for further use in the process, it is run into the tank U, where it is boiled down with steam and treated .with scrap iron for cement copper or with lead strips hung in the acid upon which crystals of copper sulfate form. These lead strips are cleaned and used again and the coppersulfate may be disposed of as desired. p

a subsidiary step' in this process, sulfurous acid may be prepared by roasting pyritic 'ore or sulfur, at some suitable point, as by causing the hot air from the furnace to pass over said sulfur or ore before passing out of the stack, and carrying the" gas evolved thereb which is sulfurous aci'd gas, in any this way, and in connection with certain ores, the sulfuric acid step of the main processes outlined above may be dispensed with. So far as this processil concerned, it isimmaterial whether the jlsing of the gas from roasting sulfur into as. mixer is said to form sulfurous or sulfiuric acid. Depending upon the amount oft-water present and thecondithrough the pipes N and N intci tion of the reaction, both acids might be present to' some extent. Under some conditions the use of sulfurous acid gas with water, preferably hot water, in the mixer may be the most desirable manner of practicing this invention. The hot water will dissolve the sulfate and a certain amount of sulfurous and sulfuric acid will be formed which will dissolve the oxid of copper, thereby obtaining a rich electrolyte, which has removed practically all the copper from the ore and which may be led directly to the electro lytic cells after separation from the insoluble matter. This combines the hot water and acid step in a single operation.

The fumes of sulfurous acid gas generated in roasting the ores in the main process,

when those ores contain sulfur, may also be i used to supply sulul'rous acid for the mixer.

It will be obvious, likewise, that the sulfurous acid as obtained in this way, as well as that obtained independently, as above described, may be led directly to the tank I, or into the electrolytic vats, .there used to form sulfurous acid, and said acid used instead of the sulfuric acid in the general process as outlined. i

Having described my invention, what I claim as new and desire to secure by Letters Patent, is I i 1. The process of extracting copper from its ores, consisting in reducing said ores to granular condition, then placing said ores within a closed leaching vessel, then introducing water and placin liquid SO into said vessel whereby free su furous acid will be formed and a solution of the copper thereby effected, then pneumatically separating said solution from the residue, then washing said residue and preserving said washin s, then subjecting said solution as an electro yte to a current of relatively low density between insoluble anodes and cathodes, maintainin an excess of sulfurous acid in said electrolyte whereb the same will be oxidized to form 'free su .furic acid, then re-employing said electrolyte depleted from copper for leaching fresh charges of ore. i

2. The process of extractingco 'per vfrom its ores, consisting in reducing sai ores to a granular condition, then-placing said ores within a closed leachin vessel, then' introducin a quantity of acldulated solution deplete from copper by electrolysis, {then orcing SO into said vessel whereby free sulfurous acid will be formed and a further so- 'lution of the copper effected, then separating said solution from the residue, then subjecting said solution as an electrolyte to a current of relativel low density between insoluble anodes lan cathodes whereby metallic co per will be deposited and the solution wi l regain its acidity, and then re-employing said solution for leaching fresh charges of ore.

IIO

,5 3. llhe process of extracting copper from its ores, consisting iii-reducing the ores to a granular condition, then roasting said ores at a relatively low temperature to convert the iron in said ores into an insoluble o id and to convert the copper into soluble form, then placing said roasted ore Within a closed eaching vessel, then introducing Water to dissolve the co per salts soluble therein, then i forcing liquid 0 into said vessel to produce free sulfurous acid whereby the hitherto un dissolved copper will be taken into solution, then pneumatically separating said solution I froni the residue, then submitting the same as an electrolyte to a current of relatively lowdensity between insoluble anodes and cathodes, maintaining an excess of sulfur- 5 ous acid whereby the copper will be deposited in metallic form and free sulfuric 3 acid formed, and then re-cinploying said electrolyte for leaching fresh charges of ore.

granular condition, then placing said ores Within a closed leaching vessel, then int-roducing- Water and forcing compressed SO;

into said vessel, whereby sulfurous acid will be formed and a solution of the copper in the I said ores effected, then separating said solution from the residue, then subjectingsald solution containing an excess of sulfurous acid as an electrolyte to a current of relatively 7 low density between insoluble anodes'and cathodes, whereby metallic copper will he deposited and the solution regain acidity and be adapted for leaching fresh charges of ore. In testimony whereof I affix my signature,

in the presence of two Witnesses.

RICHARD LAMP.

itnesses:

H. M. SEAMANS, I. (.l. Dani-ism. 

